Shigeyuki Obayashi

An inverse analysis of unobserved trigger factor for slope stability evaluation

Abstract This paper presents an inverse analysis of unobserved trigger factors for slope failures and landslides, based on structural equation modeling (SEM). Quantitative prediction models generally elucidate the relationship between past slope failures and causal factors (e.g. lithology, soil, slope, aspect, etc.), but do not consider trigger factors (e.g. rail fall, earthquake, weathering, etc.), due to difficulties in pixel-by-pixel observation of trigger factors. To overcome these, an inverse analysis algorithm on trigger factors is proposed, according to the following steps: • Step 1: The relationship between past slope failures (i.e. the endogenous variables), causal factors and trigger factors (i.e. the exogenous variables) are delineated on the path diagram used in SEM. • Step 2: The regression weights in the path diagram are estimated to minimize errors between the observed and reemerged ‘variance–covariance matrix’ by the model. • Step 3: As an inverse estimation, through the measurement equation in SEM between causal and trigger factors, a trigger factor influence (TFI) map is proposed. As an application, TFI maps are produced with respect to ‘slope failures’ and ‘landslides’, separately. As a final outcome, the differences in these TFI maps are delineated on a ‘difference’ (DIF) map. The DIF map and its interpretation are useful, not only for assessing danger areas affected by trigger factors, but also for ‘heuristic information’ in locating field measuring systems.

UTILIZATION OF THE CAKE DEHYDRATED BY VACUUM-PRESSURE DEHYDRATION EQUIPMENT AND DEVELOPMENT OF A SYSTEM TO DEHYDRATE SLURRY CONTAINING CEMENT DISCHARGED

環境問題が大ききくクローズアップされている今日, 建設分野においても掘削工事などで排出される高含水土は産業廃棄物に指定され, その処理・処分が難しいのが現状である. そこで, 筆者らはこの高含水土処理に対し低加圧と負圧を併用する新しい脱水機構を有する処理装置の開発を進めてきた. 本論文は, この装置で得られた脱水ケーキの有効利用について研究すると共に, 高含水土の内でも現在処理が難しいとされている地盤改良工事から発生する高含水セメント混入土に着目し, この処理に対する本装置を含む処理システムの適用性についてとりまとめたものである. この結果, 幅広い高含水土に対し, 本システムは有効利用を含めた処理方法として適用が可能であり, 実用化に供する方法であることを確認できた.

PRACTICAL APPLICATION OF AN APPARATUS TO IMPROVE SLURRY DISCHARGED AS CONSTRUCTION RESOURCES

建設工事で発生する泥水状の排出土は汎用的な改良方法がなく, その大部分が無処理のまま現場から産業廃棄物として搬出され, 環境面において多くの社会問題を引き起こしている. そこで, 筆者らはこの泥水状の排出土を効率良く脱水・加工し, その結果得られる改良土についても有効利用可能な装置の開発に取り組んできた. 本論文はろ材に金網を用い, 凝集剤に少量のセメントを用いる脱水方法を提示し, さらに真空脱水の有効性を紹介するとともに, 低加圧と負圧を併用した装置について示したものである. そしてこの装置によって, 高効率な脱水が可能となり, 改良土も有効利用できる強度のものが得られることがわかった.

THE DEVELOPMENT OF HIGH SPEED IMAGE PROCESSING/ANALYZING SYSTEM WITH A PERSONAL COMPUTER

本研究は, 従来大型汎用計算機の範疇であったマルチスペクトルデータの処理解析をパソコンで代替しようとするものである. 本研究で開発したシステムは, 豊富な画像処理/解析機能と高い操作性を有している. さらに, パソコンシステムの最大の障害であった処理速度を極めて高速化することに成功した. その結果, 安価なシステム構成で手軽にマルチスペクトルデータを処理/解析することが可能となった.

Evaluation of the accuracy of the geometric correction for the three different high resolution sensor data (HRV, TM and MESSR)

Abstract The information on the surface of the earth observed with the sensors mounted on artificial satellites has become to be effectively utilized in many fields. This was begun by LANDSAT, and the satellites like SPOT and MOS-1 have been operated, in this way, the fact that the observed and acquired data have become diverse contributed largely to it. These informations have become usable by the users selecting the required ones, on the other hand, a question that is it proper to utilize respective informations by the same image processing technique arose /1/. This study was to compare and evaluate the characteristics of the geometrical distortion indwelling in the satellite data obtained with three kinds of high resolution sensors, that is, MESSR(MOS-1), TM(LANDSAT) and HRV(SPOT). At the time of the precise geometrical correction processing of satellite data, this becomes a valuable guideline.